Two Part Question Help Please

I could use any help that you can offer to answer these problems or get me going:

Here is part one:
The Hot Wheels car launcher has a plastic block that can be pulled back to latch at four
different positions. As it is pulled back, it stretches a rubber band—a greater stretch for each
of the four latching positions. Your task is to determine the elastic potential energy stored in
the launcher in each of these launching positions using the generalized work-energy principle.
Equipment: Hot Wheels car, Hot Wheels track, Hot Wheels car launcher, meter stick, twometer
stick, ruler, masking tape, timer, scale to measure mass, spring scale.

Here is part two:
Your task to determine the least energy launching position so that the car will make it around
the loop without loosing contact with the loop—on the FIRST TRY (Do not use a trial and
error method). If you use the next lower energy setting, the car should not make it around the
loop. You may use the results you obtained from the previous experiment.
Equipment: Hot Wheels car, Hot Wheels track, Hot Wheels car launcher, meter stick, twometer
stick, ruler, masking tape, timer, scale to measure mass, Hot Wheels loop-the-loop and
spin-out.
Start by connecting the car launcher to a level track, which is attached to a loop-the-loop.
Place a spin-out at the end of the track (to keep the car from leaving the table).